CN104143837B - There is the inverter alternating voltage sensorless control method of parameter adaptive characteristic - Google Patents

Abstract

A kind of inverter alternating voltage sensorless control method with parameter adaptive characteristic. First with Second Order Generalized Integrator, the indifference following feature of characteristic frequency AC signal is built orthogonal filter, then use this orthogonal filter and introduce parameter adaptive control strategy, build the voltage observer of the three-phase grid-connected inverter with parameter adaptive characteristic, under biphase rest frame, to measure the grid side current signal obtained with circuit control device output bridge terminal voltage reference signal as the input of voltage observer, observe line voltage; And control in conjunction with three-phase grid-connected inverter PR under biphase rest frame, it is achieved the inverter operation when alternating voltage sensorless controls. The method can when keeping inverter control stability, avoid the problems such as integration saturated, initial value is sensitive, static error that conventional alternating voltage sensorless is likely to occur in controlling, and when grid-connected inverters impedance parameter changes, there is good adaptability.

Description

There is the inverter alternating voltage sensorless control method of parameter adaptive characteristic

Technical field

The present invention relates to the control method of a kind of three-phase grid-connected inverter.

Background technology

Regenerative resource grid-connected system development in recent years is rapid, when it accesses the power distribution network of electrical network end or grid structure comparatively weakness, would be likely to occur and site capacity of short circuit is less, grid stability is poor, and electrical network exists the problems such as comparatively serious voltage pulsation, flickering, symmetrically or non-symmetrically Voltage Drop fault. The intermittence of regenerative resource self and randomness likely worsen the voltage stability of accessed power system further, and affect the stable operation of self in turn. Grid-connected power in order to realize renewable energy system controls with electric current, existing grid-connected converter or inverter are generally adopted phaselocked loop and obtain line voltage information, but this kind of phase lock control is easily subject to the impact of voltage ripple of power network, it is easy to reduce the quality of power supply of regenerative resource grid-connected system. Therefore, some researcheres of recent domestic begin one's study be independent of mains voltage signal alternating voltage sensorless control, with improve grid-connected inverters control robustness.

Similar with there being voltage sensor to control, in Converter Without Voltage Sensor control algolithm, the voltage of reconstruct/Virtual shipyard signal can be explicit, row vector control of going forward side by side; Can also be implicit expression, and carry out direct Power Control. Existing line voltage/Virtual shipyard reconstructing method substantially can be divided into two classes, one is based on line voltage/Virtual shipyard reconstructing method that complex power is estimated, belongs to open loop method of estimation, and degree of accuracy is not high, and due to containing current differential item, thus easily caused by interference;Two line voltage/Virtual shipyard the reconstructing methods being based on current on line side bias adjustment, belong to closed loop method of estimation, and accuracy is higher.

T.Noguchi et al. proposes the direct Power Control method based on Converter Without Voltage Sensor in document " DirectpowercontrolofPWMconverterwithoutpower-sourcevolta gesensors ", this method obtains AC active reactive power first by filter inductance electric current and differential term estimation thereof, then carries out line voltage reconstruct. In order to reduce the error that differential term causes, this method needs bigger inductance value and sample frequency; It addition, when electric current is less, voltage estimated accuracy can be a greater impact. Malinowski et al. proposes to use instead integral operation, observation electrical network " Virtual shipyard " in document " Sensorlesscontrolstrategiesforthree-phasePWMrectifiers "; But pure integrator method to there is integration saturated with problems such as null offsets and initial value is comparatively sensitive.

Patent CN201010109338.2 proposes a kind of direct Power Control method of grid-connected inverter without non-AC voltage sensor, solve existing method and choose improper due to the integrator initial value in the Virtual shipyard observer of voltage on line side vector, and cause the combining inverter cannot the problem of normal operation. Patent CN201010207412.4 proposes the control method of a kind of alternating voltage sensorless high voltage direct current transmission converter, by computing system Virtual shipyard vector, it is achieved alternating voltage sensorless controls.

Alternating voltage sensorless control method described in above-mentioned document and patent generally uses the scheme based on flux observer: under synchronous coordinate system, electric current is integrated, thus obtaining " Virtual shipyard ", and indirect calculation goes out line voltage angle. In order to reduce interference, improve accuracy of observation, it is generally required to use low pass filter, but low pass filter itself also exists that null offset, integration be saturated, steady-state error and the problem such as initial value is sensitive; Additionally when line voltage is asymmetric, the Cascade algorithms that flux observation separates with positive-negative sequence adds time delay, reduces the dynamic responding speed of system.

Due to Second Order Generalized Integrator (SecondOrderGeneralizedIntegrator, SOGI) of ac of characteristic frequency can be integrated computing, therefore often it is used to build the phaselocked loop under rest frame, for single-phase or three-phase voltage source type inverter grid-connected Synchronization Control. Actually, Second Order Generalized Integrator can be used to build a kind of orthogonal filter (QuadratureFilter, QF), export the orthogonal signalling of a pair sine, and for the reconstruct of line voltage, thus realizing alternating voltage sensorless control, its advantage be quickly, floating, initial value is insensitive, the voltage observer that this orthogonal filter builds simultaneously can adapt to the change of grid-connected impedance parameter by the improvement of control strategy such that it is able to solves Problems existing during existing alternating voltage sensorless controls well. Separate it addition, utilize orthogonal signalling can also synchronously realize positive-negative sequence, thus improving the inverter dynamic property when unbalance grid.

Summary of the invention

Null offset that may be present in it is an object of the invention to overcome existing inverter alternating voltage sensorless to control, integration are saturated, steady-state error and the problem such as initial value is sensitive, and make inverter alternating voltage sensorless control can adapt to the change of grid-connected impedance parameter, it is proposed to a kind of three-phase grid-connected inverter alternating voltage sensorless control method with parameter adaptive characteristic. The present invention can when keeping inverter control stability, the problem such as avoid integration that conventional alternating voltage sensorless is likely to occur in controlling saturated, have quickly, floating, to advantages such as initial value are insensitive, the change of grid-connected impedance parameter is had good adaptability simultaneously.

A kind of inverter alternating voltage sensorless control method with parameter adaptive characteristic of the present invention, orthogonal filter is built based on Second Order Generalized Integrator (SOGI), it is then based on this orthogonal filter and introduces parameter adaptive control construction of strategy there is the line voltage observer of parameter adaptive characteristic, this voltage observer is applied in the controller of three-phase grid-connected inverter, it is achieved the alternating voltage sensorless of inverter controls.Specifically include following steps:

1, the orthogonal filter (QF) based on Second Order Generalized Integrator (SOGI) is built, this Second Order Generalized Integrator contains the second order resonance link of sinusoidal signal, sinusoidal of ac " integration " computing can be carried out, the AC signal of characteristic frequency DAZ gene control can be realized. This orthogonal filter includes the parts such as input/output signal, filter gain coefficient, Second Order Generalized Integrator, output feedack, and wherein v is filter input signal,WithFor the output signal of wave filter,WithIt is pair of orthogonal signal, whereinWith v same phase,Than v delayed 90 ��, k is filter gain coefficient. After ac input signal v enters wave filter, with the output signal of feedbackDeviation, device gain coefficient k after filtering, subsequently into Second Order Generalized Integrator, Second Order Generalized Integrator exportsWith

2, based on the orthogonal filter described in step 1 and introduce parameter adaptive control strategy, build the voltage observer with parameter adaptive characteristic, ac grid voltage is observed. The input of the described voltage observer with parameter adaptive characteristic is i_����And v_����, wherein i_����For measuring the inverter ac side electric current that the obtains component in biphase rest frame, v_����Bridge end for circuit control device output controls the voltage component in biphase rest frame; OutputFor observing the line voltage that the obtains component in biphase rest frame. Inverter ac side electric current is at the component i of biphase rest frame_����The voltage component v in biphase rest frame is controlled with circuit control device bridge end_����Respectively enter the orthogonal filter described in step 1, obtain outputWithWithIt is then based on the mathematical model of three-phase grid-connected inverter $\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=L\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+R\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right]$ It is derived by the line voltage component in biphase rest frame

Based on the orthogonal filter described in step 1, introduce impedance parameter ADAPTIVE CONTROL. Described grid-connected impedance parameter ADAPTIVE CONTROL, it is when inverter DC load is constant, makes inverter unity power factor run, with the inductance parameters in little step-size change voltage observer, when inverter ac side current amplitude is minimum, it is believed that inductance parameters matches with actual value. Parameter search program min{ | i | is designed according to this strategy }, make the i that voltage observer inputs_����Enter min{ | i | } search utility, it is thus achieved that resistance value when current amplitude is minimum, this resistance value is the grid-connected resistance value that inverter is actual. Based on the method so that described voltage observer has parameter adaptive characteristic.

3, the voltage observer with parameter adaptive characteristic based on step 1 and step 2 is applied to three-phase grid-connected inverter PR controller under �� �� coordinate system. This PR controller includes the power outer shroud based on PI and based on links such as the current inner loop of PR, PWM, wherein power outer shroud includes DC voltage outer shroud and reactive power outer shroud, control DC voltage and reactive power respectively, the meritorious reference current that DC voltage outer shroud output inverter controls, the idle reference current that reactive power outer shroud output inverter controls; Current inner loop is the PR controller under the biphase rest frame of �� ��. The line voltage of voltage observer output is at the component of biphase rest frameFollowing aspect for inverter control: 1. for calculating the actual reactive power value obtaining three-phase grid-connected inverter, as the value of feedback of reactive power outer shroud; 2. be tied to the coordinate transform of �� �� coordinate system for dq coordinate, the current reference value under the dq coordinate system export power outer shroud PI controller is transformed to the current reference value under �� �� coordinate system.Thus realizing controlling based on the three-phase grid-connected inverter alternating voltage sensorless of the method for the invention.

Accompanying drawing explanation

Fig. 1 combining inverter simple equivalent circuit model;

Fig. 2 combining inverter steady-state operation phasor diagram, wherein Fig. 2 a be inductance parameters bigger than actual value time equilibrium transport spirogram, Fig. 2 b be inductance parameters less than actual value time equilibrium transport spirogram;

Fig. 3 orthogonal filter (QF) structured flowchart;

Fig. 4 has the voltage observer structured flowchart of parameter adaptive characteristic;

Fig. 5 has the three-phase grid-connected inverter alternating voltage sensorless control block diagram of parameter adaptive characteristic;

The simulation result during change of grid-connected impedance parameter, invertor operation situation affected in Fig. 6 line voltage observer, wherein Fig. 6 a is inductance parameters change, and Fig. 6 b is voltage magnitude change, and Fig. 6 c is current amplitude change, and Fig. 6 d is inverter output reactive power.

Detailed description of the invention

The present invention is further illustrated below in conjunction with the drawings and specific embodiments.

Compare with conventional three-phase grid-connected inverter control method, alternating voltage sensorless control method proposed by the invention does not use AC voltage sensor, and use the voltage observer built based on orthogonal filter to obtain line voltage information, this voltage observer has parameter adaptive simultaneously, control thus realizing the three-phase grid-connected inverter operation when alternating voltage sensorless, and this alternating voltage sensorless control method has good adaptability when grid-connected inverters impedance parameter changes.

The present invention builds orthogonal filter based on Second Order Generalized Integrator (SOGI), it is then based on this orthogonal filter and introduces parameter adaptive control strategy, build the line voltage observer with parameter adaptive characteristic, this voltage observer is applied in the controller of three-phase grid-connected inverter, it is achieved the alternating voltage sensorless of inverter controls.

Described voltage observer can draw according to the model inference of three-phase grid-connected inverter, is shown below:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=L\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+R\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right]---\left(1\right)$

Wherein, u_��And u_����i_��And i_����v_��And v_��Respectively line voltage, inverter ac side electric current and inverter leg output voltage are at the component of biphase rest frame, and L and R is inverter outlet side equivalent inductance and resistance respectively.

Formula (1) exists the differential term of electric current, in general calculating, is readily incorporated interference. This is also that common alternating voltage sensorless controls then employing integral operation, calculates electrical network " Virtual shipyard " and indirectly obtains the reason of line voltage information; But conventional " Virtual shipyard " method exists, and null offset, integration be saturated, steady-state error and the problem such as initial value is sensitive, and dynamic response is slower. The present invention builds orthogonal filter based on Second Order Generalized Integrator, use this orthogonal filter and introduce a kind of parameter adaptive control construction of strategy line voltage observer, current differential operational problem can be solved preferably, effectively reduce harmonic wave interference, and the three-phase grid-connected inverter alternating voltage sensorless realized based on this voltage observer controls have good dynamic responding speed, the change of grid-connected impedance parameter had certain adaptability.

Observe formula (1) it is found that accurately to observe line voltage, not only need the ac current measurement value that precision is higher, in addition it is also necessary to inverter device reactor parameter accurately. In actual motion, the inductance of reactor is difficult to accurate measurement, and can change along with the change of the environmental factorss such as temperature. It addition, when grid-connected inverters works, the equiva lent impedance of circuit also often changes along with the change of the factor such as trend, network structure, thus affecting grid-connected point voltage, line voltage observation is had a negative impact. Therefore present invention research is by improving the parameter adaptive characteristic of voltage observer, thus improving alternating voltage sensorless to control the grid adaptability when circuit parameter variations.

The enforcement step of control method of the present invention described further below:

Step (1): first analyze the impact of grid-connected inverters impedance parameter change

In order to the impact of circuit parameter is described, it is possible to use simple equivalent circuit model as shown in Figure 1, and to this simplified model is made following several presupposition:

(1) inverter accesses forceful electric power net, and line voltage u is constant, merges with reactor impedance by line impedance;

(2) resistance of switching loss and wave filter on AC side is ignored;

(3) inverter direct-flow side connects a constant resistance load, and controls DC voltage U_dcRemaining unchanged, namely DC side output P is constant. The then real component i according to the known ac-side current i of alternating current-direct current power relation_dConstant:

WhereinFor the power-factor angle of also site, I_loadFor DC side electric current, Const is expressed as a certain constant.

(4) control inverter unity power factor to run. When inverter stable operation, the line voltage that observer is exported by circuit control deviceIt is directed toAxle, namelyDue to the effect of rheonome, power network currentIt is equal to reference value, then can obtain through derivation:

$\begin{array}{c}\left[\begin{array}{c}{\hat{i}}_d\\ {\hat{i}}_q\end{array}\right]=\left[\begin{array}{c}{i}_d^{*}\\ i_q^{*}\end{array}\right]=\frac{1}{{\hat{u}}_d^2+{\hat{u}}_q^2}\left[\begin{array}{cc}{\hat{u}}_d& {\hat{u}}_q\\ {\hat{u}}_q& -{\hat{u}}_d\end{array}\right]\left[\begin{array}{c}{P}^{*}\\ Q^{*}\end{array}\right]\\ =\frac{1}{{\hat{u}}_d^2}\left[\begin{array}{cc}{\hat{u}}_d& 0\\ 0& -{\hat{u}}_d\end{array}\right]\left[\begin{array}{c}{P}^{*}\\ 0\end{array}\right]=\left[\begin{array}{c}{P}^{*}/{\hat{u}}_{\mathrm{gd}}\\ 0\end{array}\right]\end{array}---\left(3\right)$

Wherein,Exist for controllerLine voltage under coordinate system and electric current.

Owing to electric current can be measured by mutual inductor measuring, thereforeOverlap with actual current i. According to formula (3),It should be zero with the angle of i. Again according to Fig. 1 can obtain inductance parameters deviation actual value time phasor relation figure, as in figure 2 it is shown, wherein Fig. 2 a be inductance parameters bigger than actual value time equilibrium transport spirogram, Fig. 2 b be inductance parameters less than actual value time equilibrium transport spirogram. Wherein line voltage u, alternating current real component i_dFor steady state value.For the inductance parameters that circuit control device uses, and L is actual inductance value. It can be seen in fig. 2 that owing to employing incorrect inductance parameters, cause that the line voltage that observer exports is misaligned with virtual voltage, thus actual power factor angleIt is not zero. Due to and the actual reactive power of site be not zero, and active power is solely dependent upon DC side, no matter thereforeBigger or little than L, actual current all can increase.

Therefore when the grid-connected impedance parameter value that circuit control device uses and actual value are inconsistent, it is possible to by judging inverter ac side current amplitude, revise grid-connected impedance parameter.

Step (2): build orthogonal filter (QF) based on Second Order Generalized Integrator (SOGI).

Second Order Generalized Integrator is capable of the tracking to characteristic frequency of ac, is used to the of ac of output pair of orthogonal the earliest, to realize positive-negative sequence separation. Feature according to its output signal, the wave filter built based on Second Order Generalized Integrator is called orthogonal filter (QF) by the present invention, and its structure is as shown in Figure 3.

As it is shown on figure 3, v is filter input signal,WithFor output signal, subscript " ^ " represents observed quantity, ��_vFor the angular frequency of ac voltage signal, k is filter gain coefficient.

Step (3): based on the orthogonal filter of step (2) and introduce parameter adaptive control strategy, builds the voltage observer with parameter adaptive characteristic.

Owing to the orthogonal signalling of sinusoidal signal are equivalent to homophase or the inversion signal of its differential, therefore following formula can be derived by based on formula (1):

$\begin{array}{c}\left[\begin{array}{c}{\hat{u}}_{\mathrm{\α}}\\ {\hat{u}}_{\mathrm{\β}}\end{array}\right]=L\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{\hat{i}}_{\mathrm{\α}}\\ {\hat{i}}_{\mathrm{\β}}\end{array}\right]+R\left[\begin{array}{c}{\hat{i}}_{\mathrm{\α}}\\ {\hat{i}}_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{c}{\hat{v}}_{\mathrm{\α}}\\ {\hat{v}}_{\mathrm{\β}}\end{array}\right]\\ =-L\left[\begin{array}{c}{\hat{i}}_{\mathrm{\α}}^{\⊥}\\ {\hat{i}}_{\mathrm{\β}}^{\⊥}\end{array}\right]+R\left[\begin{array}{c}{\hat{i}}_{\mathrm{\α}}\\ {\hat{i}}_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{c}{\hat{v}}_{\mathrm{\α}}\\ {\hat{v}}_{\mathrm{\β}}\end{array}\right]\\ =-G_{\mathrm{QF}2}L\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+G_{\mathrm{QF}1}(R\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right])\\ =G_{\mathrm{VO}}{\left[\begin{array}{cccc}{i}_{\mathrm{\α}}& i_{\mathrm{\β}}& i_{\mathrm{\α}}& i_{\mathrm{\β}}\end{array}\right]}^T\end{array}---\left(4\right)$

Wherein i_����i_��For measuring the inverter ac side electric current that the obtains component in biphase rest frame, v_����v_��Bridge end for circuit control device output controls the voltage component in biphase rest frame; OutputFor observing the line voltage that the obtains component in biphase rest frame.WithWithFor i_����i_��Output after step (2) described orthogonal filter, subscript " ^ " represents observed quantity, whereinWithWithOrthogonal signalling each other;WithWithFor v_����v_��Respectively through the output after step (2) described orthogonal filter, whereinWithWithOrthogonal signalling each other; G_VOTransmission function for line voltage observer.

In combination with described in step (2) can orthogonal filter, introduce impedance parameter ADAPTIVE CONTROL.Described parameter adaptive control strategy, it is when inverter DC load is constant, makes inverter unity power factor run, with the inductance parameters in little step-size change voltage observer, when inverter ac side current amplitude is minimum, it is believed that inductance parameters matches with actual value. Parameter search program min{ | i | is designed according to this strategy }, make the i that voltage observer inputs_����Enter min{ | i | } search utility, it is thus achieved that resistance value when current amplitude is minimum, this resistance value is the grid-connected resistance value of reality. Based on the method so that described voltage observer has parameter adaptive characteristic for the change of grid-connected impedance.

Control block diagram based on formula (4) the voltage observer introducing impedance parameter ADAPTIVE CONTROL, as shown in Figure 4, being capable of the observation to ac grid voltage, the change being simultaneous for grid-connected inverters impedance parameter has certain adaptability.

Step (4): the voltage observer with parameter adaptive characteristic of step (3) is applied in three-phase grid-connected inverter PR controller under biphase rest frame, it is achieved the alternating voltage sensorless of inverter controls.

Voltage observer substitutes into three-phase grid-connected inverter control block diagram under �� �� coordinate system, and the alternating voltage sensorless that can realize three-phase grid-connected inverter controls, as shown in Figure 5. Voltage observer PAVO therein be proposed a kind of of step (3) have parameter adaptive characteristic voltage observer, under biphase rest frame, utilize the bridge end reference voltage signal measuring the grid side current signal obtained and circuit control device output, line voltage information is observed. As shown in Figure 5, K_CFor current controller, the present invention uses conventional PR controller.

For verifying the effectiveness of control method of the present invention, MATLAB establishes inverter time domain simulation model, the control block diagram that adopts as it is shown in figure 5, simulation result as shown in Figure 6. Keeping DC voltage stability, the active power load of inverter is about 0.5p.u., and reactive power reference qref is set to 0. Make the change triangular in shape of the inductance parameters in voltage observer, as shown in Figure 6 a, then inverter device output electric current also will appear from cyclically-varying with reactive power, as shown in Fig. 6 b��6d, wherein Fig. 6 b is the comparison of actual electric network voltage magnitude (U) and voltage observer output voltage amplitude (U.ob); Fig. 6 c is inverter device output current amplitude; Fig. 6 d is inverter output reactive power. By comparing it can be seen that inverter output current minima occurs in the inductance moment close to rated value, reactive power period of change is identical with inductance period of change, and the twice that amplitude period of change is inductance period of change of electric current and observation voltage. Simulation result is consistent with theory analysis.

Claims (3)

1. an inverter alternating voltage sensorless control method with parameter adaptive characteristic, it is characterized in that, described control method is primarily based on Second Order Generalized Integrator (SOGI) and builds orthogonal filter, it is then based on this orthogonal filter and introduces parameter adaptive control construction of strategy there is the line voltage observer of parameter adaptive characteristic, described voltage observer is applied in three-phase grid-connected inverter PR controller under biphase rest frame, it is achieved the alternating voltage sensorless of inverter controls; Described orthogonal filter includes input/output signal, filter gain coefficient k, Second Order Generalized Integrator and output feedack;After ac input signal v enters described orthogonal filter, with the output signal of feedbackDeviation, device gain coefficient k after filtering, subsequently into Second Order Generalized Integrator, Second Order Generalized Integrator exportsWithThe input of the described voltage observer with parameter adaptive characteristic is i_����And v_����, wherein i_����For measuring the inverter ac side electric current that the obtains component in biphase rest frame, v_����Bridge end for circuit control device output controls the voltage component in biphase rest frame;For the line voltage of voltage observer output at the component of biphase rest frame;

Inverter ac side electric current measurement obtained is at the component i of biphase rest frame_����The voltage component v in biphase rest frame is controlled with the bridge end of circuit control device output_����Respectively through described orthogonal filter, obtain outputWith WithIt is then based on the mathematical model of following three-phase grid-connected inverter:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=L\frac{d}{dt}\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+R\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right]$

It is derived by the line voltage component in biphase rest frame

In above formula, u_��And u_��For the line voltage component in biphase rest frame, i_��And i_��For the inverter ac side electric current component in biphase rest frame, v_��And v_��For the inverter leg output voltage component in biphase rest frame, L and R is inverter outlet side equivalent inductance and resistance respectively;

Described parameter adaptive control strategy, it is when DC load is constant, makes inverter unity power factor run, with the inductance parameters in little step-size change voltage observer, when inverter ac side current amplitude is minimum, it is believed that inductance parameters matches with actual value; Parameter search program is designed so that voltage observer has parameter adaptive characteristic for the change of grid-connected impedance according to this strategy.

2. inverter alternating voltage sensorless control method according to claim 1, it is characterized in that, described Second Order Generalized Integrator comprises the second order resonance link of sinusoidal signal, sinusoidal of ac can be integrated computing, it is possible to the AC signal of characteristic frequency is realized DAZ gene control.

3. inverter alternating voltage sensorless control method according to claim 1, it is characterized in that, the described voltage observer with parameter adaptive characteristic being applied in three-phase grid-connected inverter PR controller under �� �� coordinate system, this controller includes the power outer shroud based on PI and the current inner loop based on PR; Voltage observer outputFollowing aspect for inverter control, it is achieved the alternating voltage sensorless of three-phase grid-connected inverter is controlled:

1. for calculating the actual reactive power value obtaining three-phase grid-connected inverter, as the value of feedback of reactive power outer shroud;

2. be tied to the coordinate transform of �� �� coordinate system for dq coordinate, the current reference value under the dq coordinate system export power outer shroud PI controller is transformed to the current reference value under �� �� coordinate system.